Cutaneous signs of systemic disease

Cutaneous medicine

Created 2009.

Learning objectives

Recognise skin conditions that may be signs of endocrine, gastrointestinal, haematological and nutritional diseases

Introduction

Cutaneous signs can be a clue to the diagnosis of systemic diseases or may be a complication of them requiring specific attention. More details on specific skin conditions can be found in other parts of the course or On DermNet NZ.

Endocrine disorders

Diabetes mellitus

Diabetics have an increased risk of fungal and bacterial skin infections and the complications of arteriosclerosis, diabetic vasculopathy and neuropathy.

About 50-80% of patients presenting with necrobiosis lipoidica have diabetes mellitus, most often Type 1.

There is an association with granuloma annulare especially when generalised.

Cutaneous signs of renal disease

Renal transplantation and the use of immunosuppressive medication gives rise to a high risk of viral infections (mainly warts) and skin cancers (especially squamous cell carcinomas). These may be very aggressive.

Haematological diseases

Cutaneous haemorrhages (ecchymoses and petechiae) may be due to thrombocytopaenic purpura, disseminatedintravascularcoagulation (DIC) and cryoglobulinaemia.

Generalisedpruritus can be due to iron deficiency anaemia or polycythaemia rubra vera.

Leukaemia may be associated with pyoderma gangrenosum and Sweet’s disease (acuteneutrophilicdermatosis).

Porphyria

Porphyrias are due to abnormalities of the haem pathway and result in cutaneousphotosensitivity. Diagnosis is confirmed by detection of excessive porphyrins in blood, urine or faeces. The most common to present to dermatologists are:

Sarcoidosis

Sarcoidosis is diagnosed histologically by the presence of noncaseating granulomas in the skin, lymph nodes, lungs, liver, spleen, eyes, parotid glands or joints. The mainstay of treatment is systemic corticosteroids.

Cutaneous features are highly variable:

Papules, nodules, plaques and ulcers may occur.

These may be flesh-coloured, violaceous or brown characteristically with translucent hue.